Slingsby Skylark 2

[Alan_Perse]

Hi All,

Since Bill and John are starting new builds I though I'd start mine as well.
The Plan is to build a Slingsby Skylark 2 to 1/5 Scale. Its from the Traplet plan. It will be smaller than my K8 so should be easier to transport and launch. The pic below shows what a Skylark 2 looks like.
   

Here's some pic's of what I've done so far.

[billscottni]

Builders of the world unite!   :clap:  :clap:  

Good work so far Alan. Looking forward to seeing it fly and it may be less of a handful than your K8

[Alan_Perse]

Thanks Bill.
Hopefully when I get to fly the K8 more often it will become less of a handful.

[gerryb]

yea, the building bug has really bit!  i just received plans of the manuel crested wren. this too is from traplet. model is 3m span and not too complicated. anyone wants to see this model, google 'crested wren' and check out build thread on rc groups. don't know who the builder is but he sure knows how to build a model. hope i can do as well with my model. time will tell.

[Happy Days]

Just had a look at that build thread Gerry.
There are a awful lot of radius edges in those plans, and an awful lot of plans. :?  

Good Luck to you and Alan………I recon you scale builders are all a bunch of masochists. :wink:  

Suddenly everyone has started building……..Reminds me of when my misses first became pregnant, every other woman in the street seemed to become pregnant too! :shock:  (Not by me though! :oops: )

Actually that reminds me…….our anniversary next week  ………..(No doubt we’ll observe the customary two minutes silence). :roll:

[andrew wallace]

i'm waiting on a Cliff Charlesworth  plan of a 1/4 scale ASK 13 and the lazer cut parts as well  

getting the lazor cut parts from model activity press who get belair to do the work for them so it should be good  

[Alan_Perse]

Ok. Lets get this straight. Thats Bill, John, Ralph, Me, Gerry, Andrew and probably Fred as well, all building something. I think there is going to be a shortage of wood        

[andrew wallace]

:lol:  :lol: the plan has just arrived
i'm now waiting on the lazer cut parts to arrive  :lol:

[JohnPearson]

Hi Alan,

I like this glider, should look great in the air.

Keith you should be on the comedy store LoL !

With all this building activity going on, it's going to a great year next flying season, can't wait.

[Alan_Perse]

Ok progress update.
I have all the ribs for the wings cut out, mostly. Still have the spar slots to cut out on some of them. I decided to redesign the wing using a different aerofoil, the HQ 3.5. The center panel of the three piece wing is straight so I created those ribs using the sandwich method. The pictures bellow show how I achieved this for anyone who does not know what the sandwich method is.

The Sandwich Templets
 

The Balsa blanks that go between the templets




The whole lot all bolted together


After much cutting and sanding



The finished ribs all 20 of them.

[Ron]

That's really looking good Alan    :clap:

But one question.
Why did you decide to change the aerofoil, and how did you decide on HQ 3.5?
OK, two questions :oops:

Ron

[Alan_Perse]

Hi Ron,
The HQ 3.5 Aerofoil series is the one that Chris Williams uses on his models, apparently they are supposed to give good performance. The reason I decided to redesign the wing was because after I cut out some of the ribs that are marked on the plan for the tip panel I found that some of them did not fit, which was a little annoying, also a waste of time and balsa. I also wanted to practice using my CAD drawing skills so I decided I would redesign the wings.
I'm using HQ 3.5/14 (14% thick) for the center section and HQ 3.5/14 tapering to HQ 3.5/12 (12% thick) for the outer wing panels.

[Ron]

Hi Alan,
That's interesting :?:
I have the plans for a Skylark 1, by Keith Humber, and there's no indication of what aerofoil he used.
The original used NACA 63 on the centre section and NACA 64 on the tips.
And I assume the plans don't use the original aerofoil.

I know people like Chris Williams use various 'model' oriented aerofoils, but I've often wondered if the flying characteristics may be more like the original by using the original aerofoils.

Ron

[billscottni]

At smaller scales full size airfoils don't usually work. it's all to do with Reynolds numbers.

As Alan says Chris Wiliams advocates the Quabeck sections even in his 1/3 scale aircraft

[Alan_Perse]

As far as I know the aerofoils used on full size gliders don't work very well on models, but I think there are exceptions.